Daily nasal spray of hPTH(1-34) for 3 months increases bone mass in osteoporotic subjects: a pilot study

Although intermittent parathyroid hormone (PTH) injection can lead to strong anabolic effects on bone, daily subcutaneous injection is a disadvantage for patient acceptance. We have developed a nasal spray formula of parathyroid peptide [hPTH(1-34)] with peak serum hPTH(1-34) concentrations by nasal spray of 1,000 microg similar to those by subcutaneous injections of 20 microg hPTH(1-34).

To determine the clinical efficacy and safety of nasal hPTH(1-34) spray, a randomized, open-labeled clinical trial was conducted in subjects with osteoporosis. Ninety osteoporotic subjects age 52-84 years (mean 66.5 years) were randomly assigned to receive either 250 microg (PTH250, n=31), 500 microg (PTH500, n=30), or 1,000 microg (PTH1000, n=29) of daily nasal hPTH(1-34) spray for 3 months. All received daily supplements of 300 mg calcium and 200 IU vitamin D(3).

Daily nasal hPTH(1-34) spray for 3 months increased lumbar bone mineral density (L-BMD) in a dose-dependent manner, and the PTH1000 group showed a 2.4% increase in L-BMD from baseline. Only the 1,000-microg dose produced consistent and statistically significant changes in markers of bone turnover; after 3 months, median serum type I procollagen N-propeptide (PINP) and osteocalcin increased 14.8% and 19.4% from baseline, while urinary type I collagen N-telopeptide (NTX) decreased 16.4%. Seven subjects developed transient hypercalcemia at 3 h after nasal hPTH(1-34) spray, but none of the subjects developed sustained hypercalcemia.

These observations demonstrate that nasal hPTH(1-34) spray is safe and well tolerated and can rapidly increase L-BMD. The results warrant further studies to examine its long-term efficacy on bone mass and fractures.